Good resource, even if you don't understand Japanese.
Despite not being able to read Japanese yet (slowly getting there), I still find the book to be quite clear and concise. Even just using the diagrams and posing as a reference point, I've already noticed an improvement in my own (admittedly amateurish) attempts to get back into illustration after two decades away from it.
While those who understand the language will obviously will get the most value from this book, I'm still more than satisfied with my purchase. :)